Louisa Bargeron loved the 10-foot ceilings, the fireplace with the original tile and the claw-foot tub in her one-bedroom co-op at the venerable Ontario in Washington, D.C. The hodgepodge kitchen, the cracked ancient bathroom tile and her collection of mismatched furniture — not so much.

Bargeron felt unsure of how to get her taste, personality and a bit of feminine glam into her 835-square-foot home while maintaining its historical character.

So she reached out to designers Kiera Kushlan and Jessica Centella of Residents Understood.

The designers understood why Bargeron was drawn to the Ontario, which opened in 1904 and retains its original details and charm.

“These places still have the soul of the building,” Kushlan says. “That's what brought Louisa here, and we wanted to keep that feeling.”

Bargeron, originally from New York City, moved to Washington in 2009 and bought her co-op in 2014. The Ontario reminded her of Brooklyn brownstones and Harlem prewar buildings.

“I instantly fell in love with it and wanted to live here,” says Bargeron, 43, who works at the Defense Department. The apartment has separate living and dining rooms, a compact kitchen and a long hallway leading to a bedroom and bath.

She spent nine months trying to furnish it herself.

“I was collecting and buying pieces, but I didn't know how to pull it together. There was no sort of flow or good feng shui here,” Bargeron says. “Although I was always buying things to try to overcome that, I was actually just adding to the clutter.”

She also realized the kitchen, with its jumble of different cabinets, skimpy counter space and old appliances, wasn't working. So in November 2015 she contacted Kushlan and Centella. They agreed on a plan to redo not only her kitchen but also her bathroom, and to decorate the place.

She made a Pinterest board showing what she liked and filled out their client questionnaire. “My personal style is trendy and classy. I love the color pink,” Bargeron wrote. “In terms of design, I'm anywhere from modern to traditional to French country. I can't decide on any one.”

“Louisa has a wonderful feminine style, so it was such a fun project to work on from a style perspective,” Kushlan says. “We got to pick out hot-pink rugs, fur throws and use artwork from old fashion magazines — a girl's dream.”

The kitchen was redesigned to be classic yet modern, accommodating five major appliances, including a washer-dryer set, while saving two original glass-front cabinets. On the kitchen walls, the designers used basic white subway tile in a matte finish so the counter-to-ceiling expanse didn't come across as too shiny. For the floor, they chose a black tile in a herringbone pattern.

The dining room, which has its original corner cabinets with leaded-glass detailing, was painted a warm green (Lafayette Green by Benjamin Moore).

“The dining room gets such beautiful natural light and has great white built-ins and molding, so the dark color helped to highlight those features,” Kushlan says.

The bathroom was full of century-old details, but the tile was cracking, and there was no storage. So they added marble subway tiles and 8-inch hexagonal floor tiles in dark gray. A thick crown molding dressed it up, as did the Jet Black paint by Benjamin Moore and the Restoration Hardware washstand in antiqued wood, metal and marble.